Automatic telephone system.



G. A. BETULANDER, 0. GRAHN &N. G. PALMGREN.

AUTOMATIC TEL EPHONE SYSTEM. APPLICATION FILED JAN. 18, 191B.

1,184,163 Patented May 23,1916.

' 2 SHEETS-SHEET l v 1 I 7 E5 1 3% & g w

Q. Q. flMm Qua/1. A n/4w,

- u zw w UNITED. STATESPATENT OFFICE.

F LONDON, ENGLAND. 1

- To all whom it may concern:

Be it known that .we, GQTTHILF Ansea RIUS BETULANDER, OSCAR Gem-IN, and NILs' Automatic Telephone Systems, of which the.

following is a specification.

The invention relates to automatic telephone systems of the class in which the nu-. nierical selectors-flare used for establishing but not for maintaining connections, a selector, when once a connection has been completed, disengaging itself from the 'junctionline in question, and putting itself in readiness for another call. vIn such a system the junctions are divided into groups, each having one or more selectors accessible in common to-all lines of the group'and on a call one of these selectors is automatically connected to the calling line.

The object of the present invention is by reducing the period during which a selector is engagedfor any call, to'reduce the-number of selectors required for a group of pinetion'lines, or toincrease the number of unction lines in a group. This is of special int-- portance insystems having impulse trans; mitters of the ordinary dial type, as in such systems the selector is not operated immediately on its becoming connected to they calling line owing to the fact that the setting of the dial takes some time which is longin comparison with the whole period during which the selector, is engaged, since the time occupiedby the actual working of the selector does notusuallyexceed one second. From one or other reason the time during which a selector is uselessly engaged may, of course, be rather considerable, and therefore it would be'necessary to provide every line group with two selectors at least, whereas the provision of only one selector for every group involves considerable advantages. 4

The disadvantage stated above is obviated according tothis invention by arranging that a junction shall not be marked as calling until the subscriber operates the dial Specification of Lettersl'atent.

GOT'1HILF AnseAiir-us BETULANDER, or sonnnroiiivsvnmsun," SWEDEN, joscnn GRAHN, or ennon, ENGLAND, AND mas GUNNAR museum, or sr'ocnaonm... swnnnmassrenons TO'TI-IE Repay AUTOMATIC rsnnrnonncomrnnv, LIMITED,

. "auroma'rrc TELEPHONE SYSTEM.

Patented May 23,1916.

Application fil ed January 18, 1916. Serial No. 72,709.

'whereupon a signal is'emitted,'which causes the line to be marked. The'connecting of the selector to the line is, therefore, deferred to the momentof setting the dial, preferably ample in the accompanying drawing comprising Figures land 2. These figures taken to the moment when'tlie dial is set free, and v together with Fig. 1 placed above Fig. 2

show a relay system of controlling circuit extensions,-

v The invention "is here shown as applied to a systemin. which the impulse transmitter is controlled electrmmagnetically from the exchange, so tli'at fihe impulses cannot be emitted until a selector has been connected to the junction in question. The invention is, however, not limited to systems of that kind, as it is obvious that it may be used,

with the same advantage in a system of the usual kind with uncontrolled impulse sendmg. In the example shown in the drawing all connecting operations are effected ear-1 clusively by means of relays in a known manner; The drawing illustrates a connec first group selector S, onl'ysuch of the relays tion betweena subscribers station A and a and circuits as are necessary for. explaining the invention bein shown.

The subscriber's impulse transmitter, whichis of the ordinary dial type, is only diagrammatically represented. It comprises a finger disk 1 provided with impulse with ratchet teeth 5 cooperatingwith a pawl 7 operated by an electro-magnet 6. The

pawl 7 cooperates with alever 8'in such a manner that it is held in' its inoperative position after once having disengaged the dial When the subscriber removes his receiver,

teeth 2 operating a contaotidevice 3, 4, and

s which likewise is of a from the hook 1( 3the receiver 17 and microphonelS are in the'ordmary waybranched between the line \vireslt) and 20 through a contact Qlv closed in the normal position of the dial. A circuit a is therebyclosed extending from battery througha linerelay and line branches 19 and QOQ Relay23,

upon energizing, operates a junction finder common to a group of subscribers lin es,to

test the junctions 24, 25. and to energize those relays and 31 which correspond to an: idle junction. The junction finder arrangement is not shown here as being of no importance for the present invention, but

lay 33 to battery. Relay 33ther'efore operates and cutsfinto circuit 0 a slow-acting relay 35 which closes over part of a third wire 38 extending along the talking con-.- n ect1on .'a circuit- {Z locking relays 30 and 31.

The completion of this circuit energizes a c u-t-oii'relay '36 which cuts outline relay f23.-;- The operating circuits of relays-30 v nectedto the-line until the Subscriber has 40 and -3lare thus opened but said relays iie'vertheless remain energized over circuit Relay 35 upon operating, also closes a circuit 6 over third wire 38 to a call relay assigned to theljunction 24, 2.3. Relay 41' operates and prepares the circuit of a selector connecting relay 43"pertaining to the same unction. The-selector, however, according 'to' the invention cannot be con set his dial. When the subscriber releases the dial, after having set it to the desired figure, a marking relay 44 "pertaining to the same junction-is operated-inthe mani er described belowyand'causesthe selector to be connected by means of relay 43 to the 'linei branch 24 -'over wliich the selectoris then operated.

The selector, which is common, to'a plu rality of junctions, can be connected by means-0f relays 43 to any of these ]11I'1C- tionsyrelays 44 controlling the circuits of relays-43in such a manner that only one calling unction can be connected tothe selectorat any one time as will now be described. :Relays 41, 43, 44 for only two junctions are represented.

Theconnection of the subscribers line to the junction .24, 25 has been completed vf'v'ithin a very shortfperiod of time and before the subscriber hasoperated the dial. hen the subscriber thereupon turns the dial, the receiver, and-J the microphone are cut off at"contactQIfandmagnet 6 is cut in between the line branches through contact 45 and impulse contact 3, 4. During the setting of the dial, however, magnet 6 is shortcircuited through a contact .46, which at the same time keeps the linecircuit closed. At the end of the movement of the dial contact spring 3 rests on the top of a tooth 2, contact'3, 4 being thus open, and

the point of pawl? lies between two teeth 0. At the moment when the subscriber releases the dial contact 46 is opened, whereby the line circuit is interrupted. The dial is. however, immediately turned back half a toothlthrough the action of a spring and is stopped in the corresponding position by pawl 7. In-this position contact 3, 4 is again closed. The line circuit is therefore again closed this time, however, through magnet 6. i The latter however does not operate immediately as the line current. is weakened'by resistance 32. Thebrief interruption of the line current has, however,

caused relay 33'to release its armature for amoment, whereby two circuitsf g are established, f through. a slow acting relay .49 and through relay 44. Relay 49 cuts. itself into a. locking circuit h and prepares-the circuit of a slow acting relay, Relay '44 locks itself over circuit 2'. After rela 5 33 has again attracted 1ts,ar ma,ture" and if fthe selector is engaged, nothing will occur until the selector is disengaged, asthe dial remains in its wound-up-position.

l1en the selector is set free, which is indicated by connecting relay 43 in question releasing its armature, a circuit 7; is closed.

Relay 43 operates, cuts itself into a locking circuit land connects line'branch 24- to im-- pulse relay 14 of the selector. At the same time a circuit m is closed'through the back contacts of the other relays 43 and through all switching relays 10 whereby the latter are energized. v

As the selector is now connected to the hue branch 24 a circuit it is established through relay 52 and impulse relay 14. The relay last mentioned operates and cuts slow-acting relay 12 into circuit 0.

over third wire 38. The line current is H RelayoQ attracts its I armature thereby short circuiting resistance thereby strengthened, so th-at magnet 6 at tracts'pawl 7', and releases the dial. Pawl 7 1S then retained in'its disengaged position by lever 8. During the return movement of the dial, the line circuit is broken a cer- I tain number of times at contact 3, 4. For every interruption of the current impulse relay 33 releases its armature, thereby send-- ing an impulse each time over circuit f through slow-acting relay 49 to retain its ar-- mature in .its' attracted position.v Relay 33,

each time it deenergizes, breaks circuit n of impulse relay. 14 and slow-acting'relay 52. The relay last mentioned keeps its armature attracted, While relay 14 releases its armature each time thereby sending an impulse through slow-acting relay 12 over circuit 0 to keep its armature attracted during the sending of the impulses. 'hen impulse re-.

lay 14 releases its armature for the first time,

animpulse is sent by circuit p through relay l3 and by circuit 9 q 1] through first auxiliar'y relay 11. Relay 13 operates and locks itself over part of circuit 7) and relay 11 likewise operatesand locks itself over part of circuit 9. The first switching relay 10 is, thereafter, maintained energized, as long as the impulse lasts, over circuit 1'. When the jimpulse'ceases. first switching relay lO'releases its armature. The next impulse therefore passes along circuit q Q2 19 ener:

gizing the second auxiliaryrelay 11 and the secondpair of relays 10, 11 act under the second impulse in the same manner as described in respect of the first pair of relays. Thus, .for every new impulse corresponding to an interruption of the line current a corresponding'pair of relayslO and lIis operated until the dial reaches itsnormal position.

The line circuit then remains closed through the receiver and microphone. Consequentlyimpulse relay 14 also remains energized and owing to the interruption of circuit 0 o slow-acting relay 12 releases, whereby a cir- I cuit s is closed. from earth through contacts 85 of the deenergized relays 10 andcontacts 86 of the firstenergized relay l0 and further to aswitching device (not shown) which is adapted to effect in a known manner the testing of the junction lines belonging to the group selected, and then to send a current through aconnecting relay 40 by means of which junction 24, 25 may be connected to an idle junction 87, S8 of the group selected. This operation, which has no bearing on the present invention, is fully described in the co-pending application No. 27,685 and in British-Patent No. 6210 of 1914, and need not therefore be further described in this connection. When impulse relay v33. was finally energized after the last impulse, it

'broke circuit f and therefore after an interval and subsequently to the deenergization of relaylQ slow-acting relay .49 releases its armature breaking circuit n whereby relay 52 is deprived of current. The transfer relays 33, 35, 49 and 52 belonging tothe junction 24, 25 are therefore in the same condition as before the connecting of the selector. Connecting relay 40 upon energizing, cuts itself infa known mannerpinto a locking circuit over third'wire 38. At the same time circuit 6 of relay-41is opened, said'relay in its turn opening circuits 9 5 k1 of relays 43 and 44.. \Vhen relay 43 releases its armature, the selector is restored toits normal condition. If at this moment there is a call on one ormore other junctions of the same group, a circuit t is established through back contacts of relays 44 belonging to non-calling junctions, front contact of the relay 44 belonging to the first of the calling unc- The junction in question isthereby connected to the selector as before. described. Thus, by making the markingrelays 44 control the circuits of the selector connecting relays 43 in the manner described, the object is attained that only. one calling junction is connected to the selector at any time.

By the next operation of the dial a selector of the next selecting stage is operated in a similar manner. Upon puttingback thereceiver after the termination of the conversation the line circuitis opened, the talking connection being then disconnected by rela y 35 releasing its armature and opening the locking circuits :30, 3'1 and 40. a

In case for instance two selectors are allotted to every group ofjunctions, each junction may be provided with two' selector connecting relays 43, viz., one for each selector, the circuits of which are in a similar manner controlled by corresponding marking relays actuated by the operation of the subscribers impulse transmitter for marking the junction line as calling.

- 2. In an automatic telephone system, the combination of subscribers lines, impulse transmitters at the subscribers stations, junction lines at the exchange, a numerical selector accessible in commonto a plurality of'junction lines, arelay adapted to connect the selector to a calling junction line, a marking relay adapted to control the relay first mentioned, and means actuated by the subscribers transmitter for energizingthe marking relay.

3.- In an automatic telephone system, the

combination of subscribers lines, impulsetransmitters at the subscribers. stations,

junction linesat'the exchange, a numerical selector accessiblem common to a plurality of junction lines, a 'relayassignedto each;

junction line and adapted to connect theselector to a calling junction line, a marking relay assigned to' each junction line and adapted to.control the relay first v mentioned, and means. actuatedby the subscribers transmitter for energizing the marking relay.

4. In an automatic telephone system, the combination of subscribers lines, impulse transmitters at the subscribers; stations, junction lines at the exchange, a numerical- 44 so as to prevent more'than one junction selector accessible in common to a plurality of junction lines, meansfor connecting the selector to a calling junction line, means actuated by the operation of the subscribers impulse transmitter for markingthe junction line as calling, and means for preventing more than one junction line being con-a nectedtothe selector at any one time.,'

5. In an automatic telephone system, the combination of subscribers lines, impulse transmitters at'the subscribers stations,

junctionlines at the exchange, a mimerical selector accessiblein common to a plurality of junction lines, a relay adapted to connect the selector to a calling junction line, a marking relay adapted to'control the relay first mentioned, means actuated by the subscribe'rs transmitter for energizing the marking relay, and means for preventing more than one junction line being connecterl to the selector at any one time. r v -.fi 20 6. In an automatic telephone'systenytlie' combination of subscribers lines, impulse I transmitters at the subscribers stations, junc} 'tion lines-at the exchange, a plurality of'nm' merical selector'sgeach accessible in. common to .25 a plurality of junction lines, a relay for each a selector assigned to each junction line and adapted to connect its selector tea-calling junction line, a marking relay for-each of, is relays and adapted to 3Q control such relay, andmeans actuated by the first mentioned the subscribers transmitter for energizing v one or 0th er of the marking relays. -GOTTH1LF ANSGARIUS BETULANDER.

OSCAR GRAHN.

Nils GUNNAR PALMGREN." 

